Merc SLK Wheel Bearing/Brake Noise Issue

[bennyboysvuk]

My wife has a 2004 SLK 200 which has started making a brake rubbing/wheel bearing type noise from what we think is the left side. I've looked at some things, but can't work out exactly what the issue is. Before I invest my hard-earned getting it fixed I thought I'd see what the PH brethren thought.

So, the noise occurs if it's coasting at 18-25mph. It seems to get covered up by tyre roar and wind noise above 30mph and diminishes if going much slower than 15mph.

The noise doesn't change if I apply the brakes, though I can feel the vibration through the brake pedal.

The noise doesn't change if I turn the car to the left or to the right, which makes me think it's not a wheel bearing and more likely to be the brakes. With this in mind I've taken the front pads out and made sure that they aren't contacting the run-out of the discs by chamfering the edges slightly. I've also cleaned them right up to ensure they move freely in the carrier(i.e they release ok). I've taken the discs off and cleaned up the mounting surfaces and re-fitted them. I've fitted new pads to the rear, which needed doing anyway and noticed nothing abnormal here either and no change to the noise at all.

So currently, I'm a bit flummoxed. If anyone has any ideas of how else to identify what could be making the noise, I'd be grateful for any suggestions.

Thanks.